Supporting study definitions without default groups and end_date filtering.

components/variations/variations_seed_processor_unittest.cc

Index: components/variations/variations_seed_processor_unittest.cc
diff --git a/components/variations/variations_seed_processor_unittest.cc b/components/variations/variations_seed_processor_unittest.cc
index 7703eed3b1ae1631c2f014239fc2d77dd575b1d3..d2b5130878efd65d0e0b1b7d8d067ef218bef795 100644
--- a/components/variations/variations_seed_processor_unittest.cc
+++ b/components/variations/variations_seed_processor_unittest.cc
@@ -378,8 +378,9 @@ TEST_F(VariationsSeedProcessorTest, ValidateStudy) {
   study.mutable_filter()->set_max_version("2.3.4");
   EXPECT_TRUE(processed_study.Init(&study, false));
 
+  // A blank default study is allowed.
   study.clear_default_experiment_name();
-  EXPECT_FALSE(processed_study.Init(&study, false));
+  EXPECT_TRUE(processed_study.Init(&study, false));
 
   study.set_default_experiment_name("xyz");
   EXPECT_FALSE(processed_study.Init(&study, false));
@@ -845,6 +846,23 @@ TEST_F(VariationsSeedProcessorTest, FeaturesInExpiredStudies) {
   }
 }
 
+TEST_F(VariationsSeedProcessorTest, NoDefaultExperiment) {
+  base::FieldTrialList field_trial_list(nullptr);
+
+  Study study;
+  study.set_name("Study1");
+
+  AddExperiment("A", 1, &study);
+
+  EXPECT_TRUE(CreateTrialFromStudy(study));
+
+  base::FieldTrial* trial = base::FieldTrialList::Find("Study1");
+  trial->Disable();
+
+  EXPECT_EQ(ProcessedStudy::kGenericDefaultExperimentName,
+            base::FieldTrialList::FindFullName("Study1"));
+}
+
 TEST_F(VariationsSeedProcessorTest, LowEntropyStudyTest) {
   const std::string kTrial1Name = "A";
   const std::string kTrial2Name = "B";